Telephone switch and mounting



C. L. KRUMREICH TELEPHONE SWITCH AND MOUNTING Dec. 25, 1951 2 SHEETS-SHEET 1 Filed Nov. 24, 1950 INVENTOR By C.-L.KRUMRE/CH WIRE-M Arm/Zr Dec. 25, 1951 c, KRUMREICH 2,580,105

TELEPHONE SWITCH AND MOUNTING Filed Nov. 24, 1950 SHEETS-SHEET z n m F1623 I //v VENTOR y C. L. kRUMRE/CH A T TOPNE l Patented Dec. 25, 1951 TELEPHONE SWITCH AND MOUNTING Charles L. Krumreich, Whippany, N. J assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application November 24, 1950, Serial No. 197,452

This invention relates in general to substation telephone sets and more particularly to improved means for mounting plunger operated switch assemblies employed in so-called exclusion or secrecy type subsets.

The principal object of this invention is to provide means for mounting the plunger operated switch assembly which is simple in construction, economical to manufacture, easily accessible for repair and maintenance and at the same time retains the desired features found in sets now in use.

In recent years effort has been made to design telephone sets wherein all of the components and Wiring are mounted on the base plate of said set, thereby forming a unit type chassis assembly. Since such construction enables the housing to function only as a cover for the base assembly,

4 Claims. (01. 179-159) it should be apparent that this arrangement is desirable both as to economy of manufacture and accessibility for repair in that the essential operating components are exposed in a single unit when the housing is removed. The particular type of telephone set to which this'invention relates is the so-called exclusion or secrecy subset, the operation of which has been described in the following patents: A. Tradup Patent No. 2,212,216, issued August 20, 1940 and D. H. King Patent No. 2,273,530, issued February 17, 1942. A subset of this type contains a switch assembly which serves to perform such operation as the opening of contacts to an extension telephone,

thereby securing privacy on the particular line in use. The switch is operated by a special plunger, inserted through the cradle of the desk stand, which may be lifted manually to disengage certain electrical contacts after the handset has been removed from said cradle.

In order to retain the above-mentioned design feature of the set, it is necessary that the plunger operated switch be mounted on the base plate of the desk stand. This presents an alignment problem considering that the switch and operating plunger must be located fairly accurately relative to one another for proper operation. It has been found that if both the plunger and switch are rigidly positioned with respect to the housing and base respectively, manufacturing variations will accumulate to such an order of magnitude that satisfactory alignment will rarely be realized. In order to overcome this difficulty, the present invention incorporates a floating feature in the switch mounting assembly. Such an arrangement allows the switch to move a slight amount in any direction relative to the base plate of the desk stand, thereby maintaining a correct position relative to the housing and the plunger positioned therein. In order to realize this floating feature a cantilever spring type bracket is employed to support said switch assembly above the base plate, the switch being flexibly secured to said bracket in such a manner as to be free to move slightly relative thereto.

Other objects and features not specifically pointed out will be apparent hereinafter in the description which, together with the accompanying drawings, illustrates a preferred embodiment of the invention in which:

Fig. 1 shows a plan view of the desk stand, a portion of the housing having been cut away to illustrate the plunger, switch and mounting for said switch in relation to other components of the telephone set; I

Fig. 2 shows a top view of the switch assembly and mounting;

Fig. 3 represents a side View of said switch assembly and mounting;

Fig. 4 is a wire spring for attaching the switch plate to the mounting bracket; and

Fig. 5 shows in detail the method of attaching the mounting bracket to the base of the desk stand.

Referring now to Fig. 1, base I 8 of the desk stand is enclosed by housing 10 which is provided with four upwardly extending prongs II, a pair of which are shown in cross-section. These prongs form a cradlefor supporting the handset, not shown, when the telephone is not in use. Between each pair of said prongs there is an aperture in housing It] through which the operating plungers are insertedv These comprise plunger I2 which is employed to control the contacts of secrecy switch l3, and a second plunger, not shown, inserted in thesecond aperture in housing E0 to operate the usual line contacts to connect the telephone with the line when the handset is removed from the cradle. Prior to removal of the handset from the desk stand the top of plunger i2 is held flush with the bottom of the cradle formed in housing I 0; the weight of said handset so holds the plunger in this position. Upon removal of the handset, a lever, the edge of which is designated 14 (the remainder having been cut away in Fig. l for the purpose of simplicity) exerts an upward force on shoulder I6 of plunger l2 so as to lift said plunger to the position shown. This force is supplied by coiled spring l5. In order to operate the contacts of secrecy switch l3, plunger l2 must then be gripped by knob l9 and manually lifted to the position indicated by the broken lines. This in turn will force wedge-shaped portionf'll of said plunger between the ear-shaped extensions 2B or" switch 13 so as to open contacts 2i and 22 and close contact 23, said contacts being shown in Fig. 2. It is through these contacts that the exclusion switching operation is performed. The replacing of the handset serves to depress both of said plungers to their normal non-use positions.

Since the position of plunger i2 is rigidly fixed by the aperture in housing 10 through which I said plunger slides, it is essential for operation of switch I 3 that wedge 11 be properly positioned so as to engage ears 29 of said switch. Also, since the switch assembly is to be mounted on base 18' rather than on housing 59 it is important that switch [3 have some latitude of movement so that it can assume the correct position relative to said plunger. Mounting means comprising bracket 24, switch plate 35 and wire spring 36 have been utilized in this invention to support switch It in the required manner herein set forth.

Figs. 2, 3, 4 and 5 illustrate in detail the means used to support the plunger operated switch. Bracket Ed is essentially a cantilever spring which serves to nullify all height variations between the base and housing assemblies. This is accomplished by so placing the bracket, the right end of which is secured to line switch bracket '25, attached to base plate It, that the free left end will be deflected downward by rib ii] of housing Hi thereby holding the switch in place relative to said housing. As shown in Fig. 5 the fixed end of bracket is is provided with two T-shaped extensions 25 which are inserted in two corresponding T-shaped slots 28 in bracket 26. Bracket 25 'ing T-shaped extension 38 of plate 34 and extends outward therefrom exerting pressure on ears 3!] and 3|. Plate 3d thus rests on bracket 24 at the embossed point of contact 37 and is held in place bymeans of said spring. Embossment 37 limits surface contact between the two elements thereby reducing friction, which in turn enables the switch assembly to be easily moved so as to assume its proper position relative to said plunger,

openings 32 and 33 being of sumcient size that ears 3i? and iii can move slightly therein.

The large vertical rib 46, a projection of housing Hi, serves dual functions: namely. nulliiying N height variations between base and housing, as previously described, and locating switch plate 3% in the proper front-to-back position with respect to plunger I2. Ears 4| of plate 34 form V- shaped slots which engage rib 5G, and are flared to permit easy entry of the housing at the base of the rear prong, locating the switch laterally.

It is to be understood that the particular form of this invention herein shown and described is to be taken as a preferred example of the same and that certain modifications of shape, size and assembly of parts may be resorted to without departing from the scope of said invention.

What is claimed is:

1. In a telephone desk set including a base plate, a plunger-operated switch assembly, a plunger and a housing for said set, means for mounting said switch assembly comprising a cantilever spring-type mounting bracket fixed at one end to said base plate, and means for flexibly attaching said switch assembly to the free end of said mounting bracket.

2. In a telephone desk set including a base plate, a plunger-operated switch assembly, a plunger and a housing for said set, means for mounting said switch assembly comprising a cantilever spring-type mounting bracket fixed at one end to said base plate, means for flexibly attaching said switch assembly to the free end of said mounting bracket, and means for positioning said switch assembly relative to said plunger.

3. In a telephone desk set including a base plate, a plunger-operated switch assembly, a plunger and a housing for said set provided with a rib portion thereof and an aperture therein through which said plunger operates, means for mounting said switch assembly comprising a switch plate attached to said switch assembly and provided with a plurality of upturned extensions, two of which engage the rib of said housing thereby positioning the switch assembly relative to said plunger, a cantilever spring-type mounting bracket fixed at one end to said base plate and having a plurality of upturned extensions which engage suitable slots in said switch plate, and a wire spring which presses against the extensions of the mounting bracket and switch plate thereby holding said elements together.

4. In a telephone desk set including a base plate, a plunger-operated switch assembly, a plunger and a housing for said set provided with a rib portion thereof and an aperture therein through which said plunger operates, means for mounting said switch assembly comprising a switch plate attached to said switch assembly and provided with three upturned extensions, two of which are V-shaped to permit entry of the rib of said housing thereby positioning said switch assembly relative to said plunger, a cantilever spring-type mounting bracket provided .at one end with two upturned extensions which engage suitable slots in said switch plate, the other end of said bracket having extensions which engage corresponding slots in said base plate thereby .attaching said bracket to said base plate, and a wire spring removably fixed on the third extension of said switch plate and pressing against the i upturned extensions of said mounting bracket thereby holding said elements together.

CHARLES L. KRUMIREICH.

No references cited. 

